The aims and objectives of the Tissue Core are as follows: 1) To receive, process and store blood samples in an efficient, and organized manner from CLL patients that have been diagnosed at various sites across the country. The first step will be to evaluate the suitability of the patient, collecting, testing, processing, packaging, labeling, and storing the tissue. The second step will be the distribution of the tissue to various sites for additional studies. In addition, the Tissue Core will assure accurate quality control, record keeping, and data management. Approximately 2,000 samples will be collected per year. These samples will be collected at a number of sites nationally using a uniform procedure. 2) To provide a central repository for CLL blood samples with basic minimum data information. When the samples are received by the Tissue Core, they will be assigned a unique patient identifier number and logged into a database. The sample will then be processed and viably store for future use. 3) To make the viably frozen samples readily available to other investigators across the country for future research studies. Investigators studying CLL will be able to request frozen vials by submitting the number and type of samples required and an outline of the proposed study. The approved investigators will sign an agreement regarding biohazards and commercial use of the tissue. 4) To perform basic panel of phenotypic and genetic tests on these CLL samples in a longitudinal manner pre and post therapy. The initial basic minimum set of tests that will be conducted on each patient sample will include: A- immunophenotyping analysis (Flow cytometry) to identify specific surface markers associated with CLL and immune activation, B- identification of the expressed Ig VH gene subgroup (AN-CR-ELISA), C- cytogenetic analysis to identify chromosomal abnormalities and karyotypic complexity, D- minimal residual disease testing (PCR to detect IgH rearrangements), E- microsatellite testing, a sensitive PCR technique used to screen for loss of heterozygosity that may escape conventional cytogenetic analysis.